package com.web.filter;

	import java.io.IOException;
	import java.io.UnsupportedEncodingException;
	import java.util.Map;

	import javax.servlet.Filter;
	import javax.servlet.FilterChain;
	import javax.servlet.FilterConfig;
	import javax.servlet.ServletException;
	import javax.servlet.ServletRequest;
	import javax.servlet.ServletResponse;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletRequestWrapper;
	import javax.servlet.http.HttpServletResponse;
	/**
	 * 统一编码
	 * @author Administrator
	 * 
	 */
	public class EncodingFilter implements Filter {

		@Override
		public void init(FilterConfig filterConfig) throws ServletException {
			// TODO Auto-generated method stub

		}

		@Override
		public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
			//1.强转
			HttpServletRequest request=(HttpServletRequest) req;
			HttpServletResponse response=(HttpServletResponse) resp;
			
			//2.放行
			chain.doFilter(new MyRequest(request), response);
		}

		@Override
		public void destroy() {
			// TODO Auto-generated method stub

		}

	}
	class MyRequest extends HttpServletRequestWrapper{
		private HttpServletRequest request;
		private boolean flag=true;
		
		
		public MyRequest(HttpServletRequest request) {
			super(request);
			this.request=request;
		}
		
		@Override
		public String getParameter(String name) {  
			if(name==null || name.trim().length()==0){
				return null;
			}
			String[] values = getParameterValues(name);
			if(values==null || values.length==0){
				return null;
			}
			
			return values[0];
		}
		
		@Override
		/**
		 * hobby=[eat,drink]
		 */
		public String[] getParameterValues(String name) {
			if(name==null || name.trim().length()==0){
				return null;
			}
			Map<String, String[]> map = getParameterMap();
			if(map==null || map.size()==0){
				return null;
			}
			
			return map.get(name);
		}
		
		@Override
		/**
		 * map{ username=[tom],password=[123],hobby=[eat,drink]}
		 */
		public Map<String,String[]> getParameterMap() {  
			
			/**
			 * 首先判断请求方式
			 * 若为post  request.setchar...(utf-8)
			 * 若为get 将map中的值遍历编码就可以了
			 */
			String method = request.getMethod();
			if("post".equalsIgnoreCase(method)){
				try {
					request.setCharacterEncoding("utf-8");
					return request.getParameterMap();
				} catch (UnsupportedEncodingException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}else if("get".equalsIgnoreCase(method)){
				Map<String,String[]> map = request.getParameterMap();
				if(flag){
					for (String key:map.keySet()) {
						String[] arr = map.get(key);
						//继续遍历数组
						for(int i=0;i<arr.length;i++){
							//编码
							try {
								arr[i]=new String(arr[i].getBytes("iso8859-1"),"utf-8");
							} catch (UnsupportedEncodingException e) {
								e.printStackTrace();
							}
						}
					}
					flag=false;
				}
				//需要遍历map 修改value的每一个数据的编码
				
				return map;
			}
			
			return super.getParameterMap();
		}
		
	
}
